The present invention relates, in general, to electronics, and more particularly, to methods of forming semiconductor devices and structure.
In the past, the electronics industry utilized various techniques to implement radio frequency (RF) detectors. An RF detector typically was utilized for extracting a low frequency (LF) signal that was used to modulate an RF carrier. One problem with previous RF detectors was the frequency response. Typically RF detectors were implemented in bipolar technology in order to obtain a good high frequency response. RF detectors implemented with MOS technology typically had a frequency response less than approximately 100 MHz. Because MOS technology results in lower product costs it would be desirable to have an MOS RF detector that operates at greater than 100 MHz.
Another problem with previous RF detectors was temperature stability. Typically, the output of previous RF detectors varied greater than plus or minus 5 decibels over a temperature range of xe2x88x9230 degrees to 80 degrees Celsius.
Additionally, previous RF detectors typically had distortion at the input due to impedance mismatches between the input stage and the antenna. Such mismatches resulted in harmonic distortion of the input signal. Another problem with previous RF detectors was output saturation. Typically, the input signal varied over a large range and caused the output stage of the RF detector to saturate when receiving the large input signal. Thus, such RF detectors had a small input dynamic range.
Accordingly, it is desirable to have a method of forming an RF detector that facilitates operation at high frequencies, that reduces input distortion, that has a large input dynamic range, and that has low temperature variation.